US Patent 7961278 Optical sheet stack and liquid crystal display device

There is provided an optical sheet stack which includes a first optical sheet having a large number of irregularities consecutively arranged on one surface thereof, and a second optical sheet stacked thereon. In the optical sheet stack, the second optical sheet has, on a bonding surface thereof, an adhesive layer bonded with apexes of the irregularities, and while assuming pitch of arrangement of the irregularities as P, and width of bonding of each apex of the irregularities bonded to the adhesive layer as Pw, the relation of 0<Pw/P≦0.2 is satisfied.